Varied experience is exactly what Lisa Mantchev’s protagonist seeks in Someday, Narwhal (Paula Wiseman/Simon & Schuster, $17.99). Poor tiny Narwhal, whose emotions are perfectly captured in Hyewon Yum’s expressive pictures, has grown tired of her fishbowl-confined landscape. Her friends thus help her find the courage to venture beyond the front door, where she discovers a whole world at her flippers. Ages 0-5.